Causes for a speaker to go open circuit??

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Seegs, Jul 23, 2005.

  1. Jul 23, 2005 #1
    Seegs

    Seegs Member

    Messages:
    10,149
    Joined:
    Jul 13, 2004
    Location:
    Germany
    I've had a Eminence Cannabis Rex in my 64 Deluxe and after changing power amp tubes yesterday I heard this wierd growling and scrathing sound and then nothing...

    I checked the resistance on my speaker and it read open...I put a Weber 12150F in there...changed the speaker cable just in case and it works fine...

    Could a shorted speaker cable cause the speaker to go open like that...bad output transformer or maybe just a defective speaker...??

    Any ideas would be helpful!!

    Chow,
    Seegs
     
    Seegs, Jul 23, 2005
    Seegs, Jul 23, 2005
    #1
  2. Jul 23, 2005 #2
    John Phillips

    John Phillips Member

    Messages:
    13,052
    Joined:
    Mar 17, 2002
    Location:
    Scotland
    Defective speaker or too much power.

    That's it.

    No fault on a tube amp can blow a speaker, because the speaker is isolated from the amp's circuit by the OT, and the secondary winding of the OT - the only bit that's actually connected to the speaker - is in fact a passive component.

    (A solid-state amp is different, and a shorted output transistor can easily blow a speaker by connecting it directly to the DC power supply.)

    A bad speaker cable can seriously damage an amp, but not a speaker.

    Remember that amps peak well above their rated RMS power usually though, and some speaker makers are more conservative than others about how they rate them - Celestion's definition seems to be 'a cranked tube amp of the same power' (ie possibly as much as double the RMS power they're quoting); Eminence's seems to be less.

    Even so, I don't think a 22W amp could blow a speaker rated at 50W in normal use (or even with bass through it, which reduces the effective power handling), so I'd guess you have a faulty speaker.
     
    John Phillips, Jul 23, 2005
    John Phillips, Jul 23, 2005
    #2
  3. Jul 23, 2005 #3
    Seegs

    Seegs Member

    Messages:
    10,149
    Joined:
    Jul 13, 2004
    Location:
    Germany
    Thanks John...I was hoping it was just a freak thing...I will order another one and hope it lasts longer...I have another CR in my 30-40 watt Fargen Dual classic that gets played more often and driven way harder than the speaker in my Deluxe did and it's fine...

    So maybe I was just unlucky...!!

    Chow,
    Seegs
     
    Seegs, Jul 23, 2005
    Seegs, Jul 23, 2005
    #3
  4. Jul 25, 2005 #4
    Trevor Bond

    Trevor Bond Guest

    Several things... Heat... marginal manufacturing... square wave slammin the cone...
     
    Trevor Bond, Jul 25, 2005
    Trevor Bond, Jul 25, 2005
    #4
  5. Jul 25, 2005 #5
    Wakarusa

    Wakarusa Member

    Messages:
    1,461
    Joined:
    May 7, 2004
    Location:
    Indianapolis, IN
    Depending on how long you've had it, Eminence may replace it under warranty
     
    Wakarusa, Jul 25, 2005
    Wakarusa, Jul 25, 2005
    #5

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Accept Learn More...
    Dismiss Notice